JP2007312024A - Bent broad-band antenna and method of using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, thin, and bent broad-band antenna that is effective in a broad band and can be manufactured inexpensively, and to provide a method for using the broad-band antenna. <P>SOLUTION: The bent broad-band antenna comprises: a planar conductor 1 where an external shape is rectangular and a slit 2 oriented in a direction orthogonally crossing a longitudinal direction, a side conductor 3 rising perpendicularly from a side in parallel with the slit 2 of the planar conductor 1, and a back conductor 4 installed in parallel with the planar conductor 1 from the edge of the side conductor 3 toward the side of the slit 2. A coaxial outer conductor 7 of a coaxial cable 5 is connected to the planar conductor 1 electrically at a side opposite to the side conductor 3 while sandwiching the slit 2. A coaxial center conductor 6 of the coaxial cable 5 is connected to the planar conductor 1 electrically at the same side as the side conductor 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna composed of a metal plate and a dielectric printed circuit board, and more particularly to a small and wideband antenna element and a method of using the same.

  In recent years, antennas for receiving terrestrial digital broadcasting televisions and antennas for wireless TV using UWB (Ultra Wide Band) technology have been required to have very wide band antennas.

  For example, in communication using UWB technology, a frequency band of 3.1 GHz to 4.9 GHz is assumed.

  A conventional broadband antenna has a structure as shown in FIG. This antenna is disclosed in “Patent Antenna and Television Receiver Having the Antenna” in Patent Document 1, and has a structure in which a slit 102 is provided at one end of a plate-like conductor 101 and power is supplied by a coaxial cable 105. .

  Further, recent electronic devices such as USB interface devices need to be compact as represented by USB (Universal Serial Bus) memory.

As a conventional technique related to downsizing of an antenna, there is an antenna disclosed in “Radio Device” of Patent Document 2.
JP 2005-203830 A JP 2004-215132 A

  This antenna disclosed in Patent Document 1 has a wide band characteristic, but has a drawback that the size is increased. According to Patent Document 1, the size is 210 mm × 210 mm at the minimum use frequency of 470 MHz, and the wavelength is 0.3 wavelength × 0.3 wavelength. This dimension does not sufficiently satisfy the demand for downsizing of electronic devices.

  The invention disclosed in Patent Document 2 relates to a so-called notch antenna, and it is difficult to increase the bandwidth. Further, since the circuit board itself is bent integrally, it is not only difficult to reduce the thickness, but an increase in manufacturing cost due to the bending of the circuit board is unavoidable.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a folded broadband antenna that is small and thin, effective in a wide band, and that can be manufactured at low cost, and a method of using the same.

  In order to achieve the above object, the present invention provides, as a first aspect, a plate-like conductor in which the outer shape is rectangular and a slit in a direction perpendicular to the longitudinal direction is formed from the long side, and is parallel to the slit of the plate-like conductor. A side conductor that rises vertically from one side, and a back conductor that is installed in parallel with the plate conductor from the end of the side conductor toward the slit side. A folded broadband antenna is provided in which one of the lines is electrically connected to the opposite side and the other of the lines is electrically connected to the same side as the side conductor.

  In the first aspect of the present invention, the line is a coaxial cable, the coaxial outer conductor of the coaxial cable is on the opposite side to the side conductor, and the coaxial central conductor of the coaxial cable is on the side conductor with the slit interposed. In addition to this, the coaxial outer conductor is electrically connected to the plate-like conductor at one point, or the coaxial outer conductor is a plate-like conductor. It is more preferable that they are electrically connected to each other by line contact.

  In any of the above-described configurations of the first aspect of the present invention, it is preferable that the plate conductor, the side conductor, and the back conductor are integrally formed by bending a single conductor plate.

  In order to achieve the above object, as a second aspect of the present invention, a plate-like conductor provided on one surface of a printed circuit board and provided with a slit, and a surface conductor and a back conductor are connected via a side conductor. The cross-sectional view is substantially U-shaped, and the surface conductor has a U-shaped conductor electrically connected to the plate-shaped conductor so as to cover the end of the printed circuit board. A microstrip line that forms a microstrip line in a pair with a plate-like conductor is provided across the slit on the surface opposite to the provided surface, and a U-shaped conductor is arranged rather than the slit. Provided is a folded broadband antenna characterized in that a microstrip line and a plate-like conductor are electrically connected by a through hole at a position close to the other side.

  Moreover, in order to achieve the said objective, this invention is a 3rd aspect. WHEREIN: The plate-shaped conductor provided in one side of the printed circuit board provided with the slit, and the back surface conductor provided in the other surface of the printed circuit board. And a U-shaped conductor electrically connected to the back conductor, and the printed circuit board has a plate on the surface opposite to the surface on which the plate-shaped conductor is provided. A microstrip line that forms a microstrip line paired with the conductor is provided so as to straddle the slit, and the microstrip is formed by the first through hole at a position closer to the side where the U-shaped conductor is arranged than the slit. Provided is a folded broadband antenna characterized in that a strip line and a plate-like conductor are electrically connected, and the plate-like conductor and a back conductor are electrically connected by a second through hole.

  In the 2nd or 3rd aspect of this invention, it is preferable that the slit is formed in the same direction as the longitudinal direction of a printed circuit board.

  Moreover, in order to achieve the said objective, this invention is a 4th aspect. WHEREIN: The plate-shaped conductor provided in one surface of the printed circuit board provided with the slit, and a surface conductor and a back conductor are connected via a side conductor. The cross-sectional view is substantially U-shaped, and the surface conductor is electrically connected to the plate-like conductor so as to cover the end portion of the printed-circuit board. A folded broadband antenna characterized in that a microstrip line that forms a microstrip line in a pair with a plate-like conductor is provided on a surface opposite to a surface provided with a conductor so as to straddle a slit. It is to provide.

  In the fourth aspect of the present invention, it is preferable that the line at the end of the microstrip line is enlarged to form a return loss adjusting portion.

  Moreover, in order to achieve the said objective, this invention is a 5th aspect. WHEREIN: The plate-shaped conductor provided in one surface of the insulator and provided with the slit, and a surface conductor and a back conductor are connected via a side conductor. The cross-sectional view is substantially U-shaped, and the surface conductor is electrically connected to the plate-like conductor so as to cover the end of the insulator, and the insulator has a plate-like shape. The present invention provides a folded broadband antenna characterized in that a feeding conductor is provided on a surface opposite to a surface on which a conductor is provided so as to straddle a slit.

  In the fifth aspect of the present invention, the insulator is preferably flexible. Moreover, it is preferable that the insulator is provided with means for attaching to another member.

  In order to achieve the above object, as a sixth aspect, the present invention relates to the fifth aspect of the present invention, and is a method of using a folded broadband antenna provided with a pasting means, the pasting means comprising: The present invention provides a method for using a folded broadband antenna, characterized in that the folded broadband antenna is attached to clothes.

  According to the present invention, it is possible to provide a folded broadband antenna that is small and thin, effective in a wide band, and that can be manufactured at a low cost, and a method of using the same.

[Principle of the Invention]
The folded broadband antenna according to the present invention has a configuration in which a slit 2 is provided at one end in the longitudinal direction of a plate-like conductor, a side conductor is added to one orthogonal end, and a back conductor is further added. By forming the plate-like conductor, the side conductor and the back conductor by bending one metal plate, it can be formed at low cost.
Power feeding is performed by a coaxial cable, and the coaxial outer conductor is electrically connected until just before the slit on the surface of the plate conductor described above, and the coaxial central conductor is connected to the conductor portion on the other side across the slit. . Thereby, a loop antenna effective in a wide band is formed by the plate-like conductor and the coaxial cable.
Electrically, it is possible to use a similar power feeding structure using a printed circuit board.

  An example of a preferred embodiment of the present invention based on the above principle will be described below with reference to the drawings.

[First Embodiment]
A first embodiment in which the present invention is suitably implemented will be described. FIG. 1 shows a configuration of a folded broadband antenna according to the present embodiment. In this folded broadband antenna, a slit 2 is provided at one end (long side) in the short direction of the plate-like conductor 1, a side conductor 3 is provided at one end (short side) in the orthogonal longitudinal direction, and a back conductor 4 is further added. It is a configuration.

  The width of the plate-like conductor 1 is about 0.2 wavelength in terms of the wavelength of the lowest frequency used. The depth of the slit 2 is 85% (0.17 wavelength) of the lateral width of the plate-like conductor 1. The width of the slit 2 is about 0.02 wavelength in terms of the wavelength of the lowest usable frequency to be used.

  The length of the plate-like conductor 1 in the longitudinal direction is about 0.3 wavelength in terms of the wavelength of the lowest usable frequency to be used. The length of the side conductor 3 is about 0.04 wavelength, and the length of the back conductor 4 is 0.1 wavelength.

  By forming the plate-like conductor 1, the side conductor 3, and the back conductor 4 by bending one metal plate, the manufacturing cost can be reduced.

Power feeding is performed by the coaxial cable 5. The coaxial outer conductor 7 is electrically connected to the surface of the plate-like conductor 1 where the slit 2 is provided immediately before the slit 2 (by soldering or the like), and the coaxial central conductor 6 is connected to the conductor portion on the other side across the slit 2. Are electrically connected (such as by soldering). The coaxial outer conductor 7 is soldered from the left end contact portion of the plate-like conductor 1 to the front of the slit 2.
In FIG. 1, the coaxial cable 5 is connected to the side of the plate-like conductor 1 that does not face the back conductor 4, but the coaxial cable may be connected to the side that faces the back conductor 4.

FIG. 2 shows an example of the return loss characteristic of the folded broadband antenna according to the first embodiment. The dimensions of each part are a width of 30 mm, a length of 20 mm, a back conductor width of 11 mm, a side conductor width of 4 mm, a slit length of 17 mm, and a slit width of 2 mm.
A return loss of 7.5 dB or less (VSWR 2.5 or less) is obtained in the target band of 3.1 GHz to 4.9 GHz, and sufficient performance as an antenna is obtained in the target band.

As described above, in the present embodiment, when 3.1 to 4.9 GHz is set as a target band, desired antenna characteristics can be obtained with an antenna of approximately 20 mm long × 30 mm wide × 4 mm high. In this case, since the size is 0.2 × 0.3 × 0.04 wavelength in terms of wavelength, the area occupied by the antenna can be reduced to about 2/3 compared with the prior art (Patent Document 1). .
In addition, since the circuit board itself is not bent, it can be made thinner than the prior art (Patent Document 2).

Furthermore, since the band from 470 MHz to 620 MHz has been effective conventionally, the specific band is about 28%, whereas in this embodiment, the band can be used from 3.1 GHz to 4.9 GHz, so the specific band is 45%. It becomes.
As described above, the folded broadband antenna according to the present embodiment effectively operates in a band that is nearly twice as wide as that of the conventional antenna.

[Second Embodiment]
A second embodiment in which the present invention is suitably implemented will be described. FIG. 3 shows the configuration of the folded broadband antenna according to the present embodiment. The folded broadband antenna has substantially the same configuration as that of the first embodiment, but the connection method of the coaxial cable 5 is different.

As shown in FIG. 3, only the end portion (upper end portion) of the coaxial outer conductor 7 of the coaxial cable 5 is soldered immediately before the slit 2 on the surface where the slit 2 of the plate-like conductor 1 is provided. This is a structure in which an antenna is formed.
That is, in the first embodiment, the coaxial outer conductor 7 and the plate-like conductor 1 are in line contact, whereas in this embodiment, the contact is almost point contact. Even with such a configuration, the same effect as the folded broadband antenna of the first embodiment can be obtained.

  Since other aspects are the same as those in the first embodiment, a duplicate description is omitted.

[Third Embodiment]
A third embodiment in which the present invention is preferably implemented will be described. FIG. 4 is a top perspective view of the folded broadband antenna according to the present embodiment. FIG. 5 is a bottom perspective view of the folded broadband antenna according to the present embodiment. FIG. 6 is a top view and a side view of the folded broadband antenna according to the present embodiment.

  In this embodiment, the folded broadband antenna is configured based on the printed circuit board 10. First. A plate-like conductor 11 formed of a copper foil pattern of the printed board is disposed on the bottom surface of the printed board 10. A slit 12 is formed in the plate-like conductor 11 as in the first embodiment. At one end of the short side of the plate-like conductor 11 (the right end in FIG. 4), a conductor having a U-shaped cross section formed from the surface conductor 15, the side conductor 13, and the back conductor 14 is disposed.

  In the conductor having a U-shaped cross section, the surface conductor 15 is electrically connected to the end portion of the plate-like conductor 11 (by soldering or the like).

  Power is supplied by the microstrip line 16. The microstrip line 16 disposed on the upper surface of the printed circuit board 10 and the ground 18 disposed on the bottom surface of the printed circuit board 10 function as a microstrip line. These are all formed as a copper foil pattern of the printed circuit board 10.

  The tip of the microstrip line 16 crosses the upper surface of the slit 12 and is connected to the plate-like conductor 11 through a conductive through hole 17 when it is fully crossed. Thereby, a loop antenna is formed by the plate-like conductor 11 and the microstrip line.

  Since the power feeding structure is electrically equivalent to the first embodiment, the same effect can be obtained.

[Fourth Embodiment]
A fourth embodiment in which the present invention is preferably implemented will be described. FIG. 7 is a top perspective view of the folded broadband antenna according to the present embodiment. FIG. 8 is a bottom perspective view of the folded broadband antenna according to the present embodiment. FIG. 9 is a top view and a plan view of the folded broadband antenna according to the present embodiment.
The difference from the third embodiment is that the back conductors 22 and 23 and the through holes 24 are used in place of a conductor having a U-shaped cross section (a conductor composed of the surface conductor 15, the side conductor 13 and the back conductor 14). It is a point that is configured.

  The back conductor 22 is a U-shaped conductor. The lower side of the back conductor 22 is soldered to a back conductor 23 formed of a copper foil pattern on the printed circuit board. Further, the back conductor 23 is electrically connected to the end portion of the plate-like conductor 11 by a plurality of conductive through holes 24. Since this structure is electrically equivalent to the third embodiment if the connection width between the back conductor 22 and the back conductor 23 is small, the same effect can be obtained.

[Fifth Embodiment]
A fifth embodiment in which the present invention is preferably implemented will be described. FIG. 10 shows the configuration of the folded broadband antenna according to this embodiment. The folded broadband antenna according to the present embodiment has the same configuration as that in the case where the direction of the slit 12 in the third embodiment is rotated by 90 degrees, and the plate-like conductor 31 is the plate-like conductor in the third embodiment. This corresponds to 11.

  As in the third embodiment, power is supplied by a microstrip line including a microstrip line 36 and a ground 38. However, since the direction of the slit 12 is rotated 90 degrees, the microstrip line 36 is also arranged in a direction rotated 90 degrees, and is electrically connected to the plate-like conductor 31 by the through hole 17 across the slit 12. .

  Since the folded broadband antenna according to the present embodiment is electrically equivalent to the third embodiment, the same effect can be obtained.

[Sixth Embodiment]
A sixth embodiment in which the present invention is preferably implemented will be described. FIG. 11 shows the configuration of the folded broadband antenna according to this embodiment. The folded broadband antenna has the same configuration as that obtained when the slit 12 is rotated 90 degrees in the fourth embodiment, and the plate-like conductor 31 corresponds to the plate-like conductor 11 in the fourth embodiment.

  As in the fourth embodiment, power is supplied by a microstrip line including a microstrip line 36 and a ground 38. However, since the direction of the slit 12 is rotated 90 degrees, the microstrip line 36 is also arranged in a direction rotated 90 degrees.

  Since the folded broadband antenna according to this embodiment is electrically equivalent to the fourth embodiment, the same effect can be obtained.

[Seventh Embodiment]
A seventh embodiment in which the present invention is preferably implemented will be described. FIG. 12 shows the configuration of the folded broadband antenna according to this embodiment. This folded broadband antenna has substantially the same configuration as that of the third embodiment, but is different in that it does not have a through hole.
Impedance matching is achieved by adjusting the right end of the microstrip line 16 and the length S protruding from the slit 12.

  FIG. 13 shows a configuration example of the power feeding unit. (A) is a top view, (b)-(d) shows the modification of the front-end | tip part of the microstrip line 16 in (a). (B) is a configuration in which the tip 45 is square, (c) is a tip 46 is a triangle, and (d) is a tip 47 is an ellipse. Impedance matching can be achieved by adjusting the length S protruding from the slit 12 and the shape and size of the tip. Note that the shape of the tip of the microstrip line 16 may be different from the illustrated example, and any shape can be applied as long as desired antenna characteristics can be obtained.

[Eighth Embodiment]
An eighth embodiment in which the present invention is preferably implemented will be described. FIG. 14 shows the configuration of the folded broadband antenna according to this embodiment. This folded broadband antenna is substantially the same as in the seventh embodiment, but is configured using an insulator 51 instead of the printed board 10.
The plate-like conductor 52 provided with the slits 53 is disposed on the back surface of the insulator 51, and the end portion of the plate-like conductor is folded back to the front surface side of the insulator 51. A rod-shaped conductor 54 is disposed on the front surface of the insulator 51 so as to straddle the rear slit 53. The coaxial center conductor 6 of the coaxial cable 5 is electrically connected to the rod-shaped conductor 54, and the coaxial outer conductor 7 is electrically connected to the plate-shaped conductor 52.

  The insulator 51 is a foldable insulator such as cloth, sponge, film, or FPC. The soft antenna 50 includes a magic tape (registered trademark) 55 on the back surface, and can be used by being attached to clothes or a bag.

  FIG. 15 shows a usage example of the folded broadband antenna according to the present embodiment. By providing magic tape (registered trademark) 55 on the soft antenna 50 shown in (a) and magic tape (registered trademark) 56 on the wear 60 shown in (b), as shown in FIG. An antenna can be attached. Accordingly, for example, a reception soft antenna 50 for terrestrial digital broadcasting or the like is carried with the clothes 60 attached to the clothes 60, and connected to the antenna terminal of a portable terminal with a reception function, so that viewing in a good reception state is possible. Is possible.

Each of the above embodiments is an example of a preferred embodiment of the present invention, and the present invention is not limited to these.
For example, in the above-described embodiment, a configuration using a coaxial cable for power feeding is described as an example. However, the same effect can be obtained by using a line having another structure such as a twisted pair cable.
As described above, the present invention can be variously modified.

It is a figure which shows the structure of the bending wideband antenna concerning 1st Embodiment which implemented this invention suitably. It is a figure which shows the return loss of the bending wideband antenna concerning 1st Embodiment. It is a figure which shows the structure of the bending wideband antenna concerning 2nd Embodiment which implemented this invention suitably. FIG. 6 is a top perspective view of a folded broadband antenna according to a third embodiment in which the present invention is preferably implemented. It is a bottom perspective view of the bending wideband antenna concerning a 3rd embodiment. (A) is a top view of the bending wideband antenna concerning 3rd Embodiment, (b) is a side view of the bending wideband antenna concerning 3rd Embodiment. It is a top perspective view of the bending wideband antenna concerning a 4th embodiment which carried out the present invention suitably. It is a bottom perspective view of the bending wideband antenna concerning a 4th embodiment. (A) is a top view of the bending wideband antenna concerning 4th Embodiment, (b) is a side view of the bending wideband antenna concerning 4th Embodiment. It is a top perspective view of the bending wideband antenna concerning a 5th embodiment which carried out the present invention suitably. It is an upper surface perspective view of the bending wideband antenna concerning the 6th Embodiment which carried out the present invention suitably. It is an upper surface perspective view of the bending wideband antenna concerning the 7th Embodiment which implemented the present invention suitably. (A) is a top view of the bending wideband antenna concerning 7th Embodiment, (b), (c) and (d) are figures which show the example of the shape of a connection part. It is a figure which shows the structure of the bending wideband antenna concerning 8th Embodiment which implemented this invention suitably. It is a figure which shows the usage example of the bending wideband antenna concerning 8th Embodiment, (a) is an antenna, (b) is the clothes with which an antenna is mounted | worn, (c) is the clothes with which the antenna was mounted | worn. Show. It is a figure which shows the structure of the antenna for the conventional radio | wireless apparatuses.

Explanation of symbols

1, 11, 21, 31, 52, 101 Plate conductor 2, 12, 32, 53, 102 Slit 3, 13, 33 Side conductor 4, 14, 22, 23 Back conductor 5, 105 Coaxial cable 6, 106 Coaxial center Conductor 7, 107 Coaxial outer conductor 8 Connector 10 Printed circuit board 15 Front conductor 16, 36 Microstrip line 17, 24 Through hole 18, 38 Ground 45, 46, 47 Connection 50 Soft antenna 51 Insulator 54 Bar conductor 55, 56 Magic Tape (registered trademark)
60 clothes

Claims (14)

A plate-like conductor having a rectangular outer shape and a slit formed in a direction perpendicular to the longitudinal direction from the long side;
A side conductor rising vertically from a side parallel to the slit of the plate-like conductor;
A rear conductor installed in parallel with the plate conductor from the end of the side conductor toward the slit side,
One of the lines is electrically connected to the plate-like conductor on the opposite side of the side conductor across the slit, and the other of the line is electrically connected to the same side as the side conductor. Broadband antenna.   The line is a coaxial cable, and the coaxial outer conductor of the coaxial cable is on the side opposite to the side conductor with the slit interposed therebetween, and the coaxial center conductor of the coaxial cable is on the same side as the side conductor with the slit interposed therebetween. 2. The folded broadband antenna according to claim 1, wherein the folded broadband antenna is electrically connected.   3. The folded broadband antenna according to claim 2, wherein the coaxial outer conductor is electrically connected to the plate conductor at one point.   3. The folded broadband antenna according to claim 2, wherein the coaxial outer conductor is electrically connected by line contact with the plate-like conductor.   5. The folded broadband antenna according to claim 1, wherein the plate conductor, the side conductor, and the back conductor are integrally formed by bending a single conductor plate. A plate-like conductor provided with a slit provided on one surface of the printed circuit board;
The surface conductor is electrically connected to the plate-like conductor so as to cover the end of the printed circuit board in a substantially U-shaped cross-sectional view in which a surface conductor and a back conductor are connected via a side conductor. With a U-shaped conductor,
The printed circuit board is provided with a microstrip line that forms a microstrip line paired with the plate-like conductor so as to straddle the slit on a surface opposite to the surface on which the plate-like conductor is provided. And
A folded broadband antenna, wherein the microstrip line and the plate-like conductor are electrically connected by a through hole at a position closer to the side where the U-shaped conductor is disposed than the slit. A plate-like conductor provided with a slit provided on one surface of the printed circuit board;
A back conductor provided on the other surface of the printed circuit board;
A substantially U-shaped cross-sectional view, having a U-shaped conductor electrically connected to the back conductor,
The printed circuit board is provided with a microstrip line that forms a microstrip line paired with the plate-like conductor so as to straddle the slit on a surface opposite to the surface on which the plate-like conductor is provided. And
The microstrip line and the plate-like conductor are electrically connected by a first through hole at a position closer to the side where the U-shaped conductor is disposed than the slit,
The folded broadband antenna, wherein the plate-like conductor and the back conductor are electrically connected by a second through hole.   The bent broadband antenna according to claim 6 or 7, wherein the slit is formed in the same direction as the longitudinal direction of the printed circuit board. A plate-like conductor provided with a slit provided on one surface of the printed circuit board;
The surface conductor and the back conductor are connected to each other through a side conductor, and are substantially U-shaped in cross-section, and the surface conductor is electrically connected to the plate-like conductor so as to cover the end of the printed circuit board. With a U-shaped conductor,
The printed circuit board is provided with a microstrip line that forms a microstrip line paired with the plate-like conductor so as to straddle the slit on a surface opposite to the surface on which the plate-like conductor is provided. A folded broadband antenna characterized by   The folded broadband antenna according to claim 9, wherein a line at an end of the microstrip line is enlarged to form a return loss adjusting unit. A plate-like conductor provided on one surface of the insulator and provided with a slit;
The surface conductor and the back conductor are connected to each other through a side conductor, and the surface conductor is electrically connected to the plate-like conductor so as to cover the end of the insulator. With a U-shaped conductor,
A folded broadband antenna, wherein the insulator is provided with a feeding conductor on a surface opposite to a surface on which the plate-like conductor is provided so as to straddle the slit.   The folded broadband antenna according to claim 11, wherein the insulator is flexible.   The folded broadband antenna according to claim 11 or 12, wherein the insulator is provided with means for attaching to another member.   14. The method of using a folded broadband antenna according to claim 13, wherein the folded broadband antenna is attached to a garment using the attaching means.

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